#include "master.hpp" namespace factor { cell string_nth(string* str, cell index) { /* If high bit is set, the most significant 16 bits of the char come from the aux vector. The least significant bit of the corresponding aux vector entry is negated, so that we can XOR the two components together and get the original code point back. */ cell lo_bits = str->data()[index]; if((lo_bits & 0x80) == 0) return lo_bits; else { byte_array *aux = untag(str->aux); cell hi_bits = aux->data()[index]; return (hi_bits << 7) ^ lo_bits; } } void set_string_nth_fast(string *str, cell index, cell ch) { str->data()[index] = ch; } void set_string_nth_slow(string *str_, cell index, cell ch) { gc_root str(str_); byte_array *aux; str->data()[index] = ((ch & 0x7f) | 0x80); if(str->aux == F) { /* We don't need to pre-initialize the byte array with any data, since we only ever read from the aux vector if the most significant bit of a character is set. Initially all of the bits are clear. */ aux = allot_array_internal(untag_fixnum(str->length) * sizeof(u16)); write_barrier(str.untagged()); str->aux = tag(aux); } else aux = untag(str->aux); aux->data()[index] = ((ch >> 7) ^ 1); } /* allocates memory */ void set_string_nth(string *str, cell index, cell ch) { if(ch <= 0x7f) set_string_nth_fast(str,index,ch); else set_string_nth_slow(str,index,ch); } /* Allocates memory */ string *allot_string_internal(cell capacity) { string *str = allot(string_size(capacity)); str->length = tag_fixnum(capacity); str->hashcode = F; str->aux = F; return str; } /* Allocates memory */ void fill_string(string *str_, cell start, cell capacity, cell fill) { gc_root str(str_); if(fill <= 0x7f) memset(&str->data()[start],fill,capacity - start); else { cell i; for(i = start; i < capacity; i++) set_string_nth(str.untagged(),i,fill); } } /* Allocates memory */ string *allot_string(cell capacity, cell fill) { gc_root str(allot_string_internal(capacity)); fill_string(str.untagged(),0,capacity,fill); return str.untagged(); } PRIMITIVE(string) { cell initial = to_cell(dpop()); cell length = unbox_array_size(); dpush(tag(allot_string(length,initial))); } static bool reallot_string_in_place_p(string *str, cell capacity) { return in_zone(&nursery,str) && (str->aux == F || in_zone(&nursery,untag(str->aux))) && capacity <= string_capacity(str); } string* reallot_string(string *str_, cell capacity) { gc_root str(str_); if(reallot_string_in_place_p(str.untagged(),capacity)) { str->length = tag_fixnum(capacity); if(str->aux != F) { byte_array *aux = untag(str->aux); aux->capacity = tag_fixnum(capacity * 2); } return str.untagged(); } else { cell to_copy = string_capacity(str.untagged()); if(capacity < to_copy) to_copy = capacity; gc_root new_str(allot_string_internal(capacity)); memcpy(new_str->data(),str->data(),to_copy); if(str->aux != F) { byte_array *new_aux = allot_byte_array(capacity * sizeof(u16)); write_barrier(new_str.untagged()); new_str->aux = tag(new_aux); byte_array *aux = untag(str->aux); memcpy(new_aux->data(),aux->data(),to_copy * sizeof(u16)); } fill_string(new_str.untagged(),to_copy,capacity,'\0'); return new_str.untagged(); } } PRIMITIVE(resize_string) { string* str = untag_check(dpop()); cell capacity = unbox_array_size(); dpush(tag(reallot_string(str,capacity))); } PRIMITIVE(string_nth) { string *str = untag(dpop()); cell index = untag_fixnum(dpop()); dpush(tag_fixnum(string_nth(str,index))); } PRIMITIVE(set_string_nth_fast) { string *str = untag(dpop()); cell index = untag_fixnum(dpop()); cell value = untag_fixnum(dpop()); set_string_nth_fast(str,index,value); } PRIMITIVE(set_string_nth_slow) { string *str = untag(dpop()); cell index = untag_fixnum(dpop()); cell value = untag_fixnum(dpop()); set_string_nth_slow(str,index,value); } }